Indigenous Knowledge and Pharmaceuticals - [API] Network

Indigenous Knowledge and Pharmaceuticals
Marcello Pennacchio and Emilio L Ghisalberti
The early European explorers were intrigued by the fact that humans could exist
in the harsh and forbidding environment of the Australian desert. Colonel Peter
Egerton-Warburton, one of the first explorers into the north-western area of Central
Australia commented ‘The country is terrible. I do not believe that men ever
traversed so vast an extent of continuous desert’. 1 The truth was that desert
Aboriginal people did cross the desert and their ability to survive in this environment
of extremes is a testament to their inventiveness and adaptability. A strong link
was forged between these desert dwellers and the land over countless generations.
An intimate knowledge of the land and its resources, and the ability to manage
and utilise them, provided the desert people with material and spiritual sustenance.
Plants played a crucial role as a source of materials, implements, food, medicine
and also as suppliers of the most important factor in desert survival — water. It
follows that a good knowledge of the botany of the regions they traversed was
required to identify and distinguish food, medicinal and poisonous plants. Their
extensive use of medicinal plants has been realised only recently and several
attempts to collect this knowledge before it is irretrievably lost have been made.
In the sequel, the use of plants as medicines by the desert Aboriginal people is
considered. A case study involving Eremophila species, members of which were
commonly used for medicinal purposes, is presented to illustrate that the use of
remedies prepared from these plants have pharmacological validity.
The Aboriginal people arrived in Australia from the tropical north and settled
the continent more than 50,000 years ago. The isolation of the land mass meant
that they had to adapt to the unusual and unique flora available and to identify
those plants that could be used for curative purposes. 2 New plants would have
been tested for their effect in treating illnesses by a process of trial and error; the
sick, frail and elderly probably serving as test subjects. Once established as a
useful species, information about a plant was passed on by word of mouth to the
next generation of ‘medicine men’.
It is important to realise that the plant medicines required by the desert
people did not have to work miracles since life-threatening diseases were not
common. Contagious and infectious diseases such as cholera, smallpox, tuberculosis,
measles and mumps were unknown until the arrival of the first European settlers. 3
Most problems were related to skin disorders, antiseptic needs, fever, rheumatic
pain, sprains, wounds and burns, in which case plant preparations were used
externally as skin washes. 4 Infusions and decoctions were also prepared, a few
of which were taken for internal complaints. Reportedly, these were used as
analgesics, expectorants and abortifacients, as well as for treating colds, influenza
and headaches. 5 Internal complaints were considered to be spiritual in nature,
and were often treated by spiritual means through the agency of the ‘medicine
men’. It comes as no surprise to find that only approximately 10 per cent of
Aboriginal medicines were ingested to treat internal disorders. 6

The Beautiful and the Damned
The leaves and the bark were the plant parts most commonly used in the
preparation of bush medicines. 7 The plant material was treated by grinding, bruising
or maceration processes, followed by extraction for decoctions and infusions. Inland
Aborigines, who did not have access to boiling implements, carried out their extractions
by soaking the plant material overnight in water or by pounding to make a paste
which was mixed with fat to prepare an ointment. Those living in coastal regions
used old baler shells to boil plant material. 8
Because of their nomadic nature, the Aboriginal people would have targeted
a variety of plants with a broad spectrum of medicinal uses rather than carry
several species with them. Of the 70 plant species know to have been used for
therapeutic purposes, about a third were either Acacias or Eremophilas. In
particular, a number of Eremophila species featured prominently in the cultural,
religious and material aspects of everyday life. 9
Eremophila (Myoporaceae) (Gr. Eremos, desert; phileo, to love) is a genus
unique to Australia. It is of widespread distribution and occurs along the coastal
margins and the hinterland, but is virtually absent in tropical zones. This preference
for areas of low rainfall and high temperatures has lead to an abundance of the genus
in the semi-arid and arid zones of Australia. Many of the 300 or so recognized species
and sub-species are tolerant to droughts, fire and grazing, as well as to light frost, and
are often found flourishing in poor soils. 10 The name ‘emu bush’ is also commonly
used and is derived from the fact that emus (Dromaius novahollandiae) feed on the
fleshy fruits of some species, eg, E maculata. 11
It is of some interest to note that a high proportion of Eremophila species
were used to prepare medicines to deal with internal complaints. Of these, E
alternifolia and E longifolia, appeared to be important in the pharmacopoeias of
the Australian Aboriginal people. 12 E alternifolia was considered the ‘number one
medicine’ by some tribes 13 and it was one of few species in which the leaves were
harvested, dried and carried around in case of need. 14 Infusions of E alternifolia
leaves were used to treat colds, influenza and headaches, 15 to induce sleep 16 and
pleasant dreams. 17 They apparently showed analgesic and decongestant properties
and were reported to promote general well-being. 18 E longifolia is a plant of
sacred and mystical significance to the Aboriginal people. 19 Its medicinal uses
include the burning of E longifolia twigs (‘smoke treatment’) near trenches, in
which newly born babies and their lactating mothers lay. Reportedly, this induces
lactation in the mother and strengthens the babies. 20 In addition, decoctions of the
leaves were used as eye washes, 21 as counter-irritants 22 and for skin and body
washes. 23 An infusion of the leaves was prepared for colds and headaches 24 and
this treatment was reported to induce restful and restorative sleep.
Of the curative properties attributed to these plants, those associated with a
feeling of well-being and induction of restorative sleep suggested to us a possible
cardioactive action. We therefore sought to establish if extracts from these plants
showed cardioactivity and, if so, to isolate and identify the active principles.
A methanolic extract from the leaves of E alternifolia was tested on
Langendorff rat hearts and was shown to mediate significant increases in heart rate
(chronotropism), contractile force (inotropism) and coronary perfusion rate (CPR)
(Pennacchio et al., 1995). The active constituent in E alternifolia leaves was
identified as the known phenylethanoid glycoside, verbascoside. Its effects on the
Langendorff rat heart were identical to those induced by the methanolic extract
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Marcello Pennacchio and Emilio L Ghisalberti
of E alternifolia leaves, but were more pronounced. A solution of verbascoside
(1ml of 1 mM) increased chronotropism, inotropism and CPR in rat hearts in a
dose-dependent manner. 25 Subsequent studies have shown that verbascoside
increases the intracellular levels of a messenger (cyclic 3, 5’-adenosine
monophosphate; cAMP). 26 The increase in cAMP production appears to occur
in response to an increase in prostacyclin. Significant increases in the levels of
this hormone-like substance were detected in hearts treated with verbascoside. 27
The presence of verbascoside in E alternifolia leaves may explain why
this species was so highly ‘prized’ by the Aboriginal people. Verbascoside has
been shown to have a range of pharmacological activities including antibacterial,
antioxidant and analgesic effects. 28 Its ability to dilate blood vessels and reduce
blood pressure 29 may account for the reports that infusions of E alternifolia leaves
helped to induce sleep and promote general well-being.
Pharmacological testing of the methanolic extract of E longifolia leaves
indicated that it also displayed cardioactivity. However, a biphasic effect on the
Langendorff rat heart suggested that more than one active compound was responsible
for the cardioactivity observed. 30 The major active constituents were identified as
geniposidic acid and verbascoside. Unlike verbascoside, which had a positive effect
on rat hearts, geniposidic acid (1ml of 1 mM) significantly inhibited chronotropism,
inotropism and CPR. 31 The presence of two bioactive compounds with apparently
opposite action is interesting. In particular, the effects induced by the two compounds
are not in phase, thus exerting a stabilising effect on the heart action.
In an extension of this study, three other species of Eremophila were
shown to contain compounds similar to geniposidic acid that significantly altered
myocardial activity in the isolated rat heart preparations. 32 The multifaceted
pharmacological actions of verbascoside, geniposidic acid and related compounds
are well documented. 33
These results indicate that, at least for the more commonly used Eremophila
species, the desert Aborigines had selected plants with distinct curative properties.
All the effects attributed to medicines prepared from these plants cannot be
rationalised by the presence of verbascoside and geniposidic acid alone. Since
both species contain a number of other compounds, it is probable that some of
these may contribute to the other beneficial effects associated with these
preparations. For example, E longifolia contains large amounts of volatiles (up
to 6 per cent essential oil) consisting of safrole (anaesthetic and bactericidal action)
and methyl eugenol (anaesthetic, bactericide, fungistatic, sedative actions). It is
possible that the presence of these compounds might explain the use of this plant
for preparations for eye, skin and body washes and as a counterirritant.
In conclusion, the use of traditional knowledge as a guide to discovering
new medicines (ethnopharmacology) has proven to be valuable in our studies and
those of others. Ethnopharmacology is a multidisciplinary study involving both the
natural sciences (chemistry, medicine, botany and pharmacology) and the
humanities (history, linguistics and ethnology). Aimed primarily at investigating
age-old practices and cultures, it affords a better understanding of the therapeutical
basis of traditional healing methods and also helps preserve traditional medical
practices and knowledge.
175

Notes to pp 219–222
Indigenous Knowledge and Pharmaceuticals
Marcello Pennacchio and Emilio L Ghisalberti
1 Cited in P K Latz, Bushfires and Bushtucker: Aboriginal Plant Use in Central Australia, Alice
Springs, IAD Press, 1995.
2 L J Webb, ‘“Eat, Die, and Learn” — The Botany of the Australian Aborigines’, Australian
Natural History, 1973, pp 290-295.
3 G F Vaughan, ‘Australian Medicinal Plants’ in R P Steiner (ed.), Folk Medicine, The Art and
Science’, Washington, American Chemical Society, 1986, pp 103-109; E V Lassack, and T McCarthy,
Australian Medicinal Plants, Australia, Methuen, 1990, p 240.
4 Latz, 1995, op. cit.; Vaughan, 1986, op. cit.
5 A Barr, Traditional Bush Medicines: An Aboriginal Pharmacopoeia, Aboriginal Communities of the
Northern Territory of Australia, Richmond, Victoria, Greenhouse Publications, 1988, p 256; A Barr,
Traditional Aboriginal Medicines in the Northern Territory of Australia, Darwin, Conservation
Commission of the Northern Territory of Australia, 1993, p 650; T Low, Bush Medicine: A Pharmacopoeia
of Natural Remedies , Australia, Collins/Angus and Robertson Publications, 1990, p 238.
6 Latz, 1995, op. cit.
7 E Reid, ‘The Records of Western Australian Plants Used by Aboriginals as Medicinal Agents’.
School of Pharmacy Project, Curtin University of Technology, 1979, p 198; Low, 1990, op. cit.
8 Barr, 1993, op. cit.
9 G S Richmond, ‘A Review of the Uses of Eremophila (Myoporaceae) by Australian Aborigines’,
Journal of Adelaide Botanic Gardens, no 15, 1993, pp 101-107.
10 R J Chinnock, Flora of South Australia, Part III Polemoniaceae-Compositae, Adelaide, South
Australian Printing Division Publications, 1986, pp 1325-1345, and personal communication; W
R Elliot and D L Jones, Encyclopaedia of Australian Plants Suitable for Cultivation, vol 3, Melbourne,
Lothian Publications, 1984, p 516.
11 Richmond, 1993, op. cit.
12 Richmond, 1993, op. cit; G S Richmond and E L Ghisalberti, ‘The Australian Desert Shrub
Eremophila (Myoporaceae): Medicinal, Cultural, Horticultural and Phytochemical Uses’, Economic
Botany, vol 48, 1994, pp 35-59.
13 Barr, 1993, op. cit.
14 Low, 1990, op. cit.
15 N M Smith, ‘Ethnobotanical Notes From the Northern Territory, Australia’, Journal of the Adelaide
Botanic Gardens, no 14, 1991, pp 1-65.
16 N B Tindale, Vocabulary of Pitjandjarra, the Language of the Native of the Great Western Desert,
Adelaide, 1931-1937, typescript, 1937.
17 Latz, 1995, op. cit.
18 Richmond and Ghisalberti, 1994, op. cit.
19 Barr, 1993, op. cit.
20 C Chewings, Back in the Stone Age. The Natives of Central Australia, Sydney, Angus and Robertson,
1936; Latz, 1995, op. cit.
21 J F O’Connell, P K Latz and P Barnett, ‘Traditional and Modern Plant Use Among the Alyawara
of Central Australia’, Economic Botany, vol 31, 1983, pp 80-109.
22 Richmond, 1993, op. cit.
23 G B Silberbauer, ‘Ecology of the Ernabella Aboriginal Community’, Anthropological Forum 3,
1971, pp 21-36.
24 W B Spencer and F J Gillen, The Native Tribes of Central Australia, New York, Dover, 1969.
25 M Pennacchio, Y M Syah, E L Ghisalberti and E Alexander, ‘Cardioactive Compounds from
Eremophila Species’, Journal of Ethnopharmacology, no 53, 1996, pp 21-27.
26 ibid.
27 ibid.
28 C Jiménez and R Riguera, ‘Phenyethanoid Glycosides in Plants: Structure and Biological Activity’,
Natural Products Reports, no 11, 1994, pp 591-606.
29 M Ahmad, C H Rizwani, K Aftab, V U Ahmad, A H Gilani and S P Ahmad, ‘Acteoside: A New
Antihypertensive Drug’, Phytotherapy Research, no 9, 1995, pp 525-527.
30 M Pennacchio, E Alexander, E L Ghisalberti and G S Richmond, ‘Cardioactive Effects of Eremophila
Alternifolia Extracts’, Journal of Ethnopharmacology, vol 47, 1995, pp 91-95.
283

Notes to pp 209–212
31 Pennacchio, et al., 1996, op. cit.
32 M Pennacchio, Y M Syah, E L Ghisalberti and E Alexander, ‘Cardioactive Iridoid Glycosides from
Eremophila Species’, Phytomedicine, no 4, 1997, pp 325-330.
33 E L Ghisalberti, ‘Biological and Pharmacological Activity of Naturally Occurring Iridoids and
Secoiridoids’, Phytomedicine, no 5, 1998, pp 147-163.
284